ProductWiki has posted a tutorial on hacking your Xbox to run the free, open-source Xbox Media Center.

So you've heard rumors of, or perhaps seen friends with, a pimped out Xbox running Xbox Media Center. They are streaming their favorite TV shows, movies, mp3s, and pictures all to their kickass home theater, and now you want some of that action. This guide is written to help you get from a standard Microsoft Xbox to a Xbox Media Center in a relatively short time with the least amount of headaches.

The time and money investment looks minimal, and if you've got an Xbox but are dying of 360 envy, maybe this will cheer you up a bit.